Typically, a syringe is filled manually by aspirating a liquid pharmaceutical component from a pharmaceutical vial which has a penetrable closure. The syringe has a needle that penetrates the penetrable closure following which the syringe is typically filled by drawing air into the body of the syringe, aligning the needle with the vial's penetrable closure and inserting the needle through the penetrable closure into the vial. Subsequently, the vial is inverted and air is forced from the body of the syringe into the body of the vial. The plunger is then withdrawn to draw out the desired volume of the pharmaceutical component into the syringe and the needle is removed from the vial.
The above reconstitution is done since many pharmaceutical preparations must be distributed and sold as two separate components—typically a solid component and a liquid component. They are mixed just prior to administration. Actually, two or more components may each be liquid.
Typically, many procedures call for the needle to be removed from the syringe since there is danger of contamination of the needle. Furthermore, the silicone on the needle may be removed during the act of penetrating the vial.